OKHSC COBRE: OXIDATIVE STRESS AND INFLAMMATION IN DIABETIC RETINOPATHY

这个子项目是许多研究子项目中利用 资源由NIH/NCRR资助的中心拨款提供。子项目和 调查员(PI)可能从NIH的另一个来源获得了主要资金， 并因此可以在其他清晰的条目中表示。列出的机构是 该中心不一定是调查人员的机构。 糖尿病视网膜病变(DR)在美国是导致失明的主要原因。DR的早期病理特征包括视网膜血管细胞功能障碍、血-视网膜屏障(BRB)破坏、血管渗漏和神经变性。尽管其机制尚不清楚，但最近的研究表明，氧化应激和炎症在色素上皮源性因子(PEDF)的发病机制中起着关键作用。 一种内源性血管生成抑制因子。越来越多的证据表明，PEDF在DR中的有益作用，即抑制视网膜新生血管和减少血管渗漏，但其机制尚未完全阐明。我们最近的新研究表明，PEDF是一种有效的抗炎因子和 抑制DR的血管渗漏。此外，PEDF可减少糖尿病引起的视网膜周细胞和糖尿病视网膜中超氧化物(O2.-)和过氧亚硝酸盐(ONOO-)的产生。基于这些重要的发现，我们假设PEDF通过减少氧化应激来改善糖尿病视网膜并发症 和炎症。在目标1中，我们将通过检测PEDF对培养的视网膜内皮细胞和视网膜神经元O2-/ONOO生成、促炎因子表达、内皮紧密连接和神经元变性的影响，来确定PEDF作为内源性抗氧化因子的活性。我们还将确定在视网膜中过度表达或下调PEDF是否会改善或增强 通过比较糖尿病和正常年龄匹配的PEDF转基因小鼠、PEDF缺陷小鼠和野生型小鼠的这些参数，研究DR中的氧化应激和炎症。在目标2中，我们将探索PEDF抑制O2.-/ONOO-形成的机制。我们推测PEDF通过上调抗氧化酶和/或保护线粒体功能来抑制糖尿病诱导的O2-产生。如果我们的 假设得到证实，我们将继续探索PEDF如何调节抗氧化酶和/或PEDF如何保护线粒体功能的信号通路。如果结果表明其他机制也可能有助于PEDF的抗氧化作用，我们将另选确定PEDF是否以及如何 通过抑制主要的氧化还原酶，即NADPH氧化酶、黄嘌呤氧化酶和eNOS，减少超氧化物的产生。该项目的成功不仅将确定DR的一种新的致病机制，还将有助于开发使用内源性血管生成抑制物的新疗法。

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Diabetic retinopathy (DR) is a leading cause of blindness in the US. The early pathologic hallmarks of DR nclude retinal vascular cellular dysfunction, blood-retinal barrier (BRB) breakdown, vascular leakage and neural degeneration. Although the mechanisms largely unknown, recent studies suggest that oxidative stress and inflammation plays a critical role in the pathogenesis of DR. Pigment epithelium-derived factor (PEDF) is an endogenous angiogenic inhibitor. Accumulating evidence suggests beneficial effects of PEDF in DR, i.e. nhibition of retinal neovascularization and reduction of vascular leakage; however, the mechanisms are not fully elucidated. Our recent novel studies demonstrated that PEDF is a potent anti-inflammatory factor and inhibits vascular leakage in DR. Moreover, PEDF reduces diabetes-induced superoxide (O2.-) and peroxynitrite (ONOO-) production in retinal pericytes and in diabetic retina. Based on these important findings, we hypothesize that PEDF ameliorates diabetic retinal complications by reducing oxidative stress and inflammation. In Aim 1, we will focus on establishing the activity of PEDF as an endogenous anti-oxidant factor by determining the effects of PEDF on O2.-/ONOO- generation, pro-inflammatory factor expression, endothelial tight junction and neuron degeneration in cultured retinal endothelial cells and retinal neurons. We will also determine if over-expressing or down-regulating PEDF in the retina will ameliorate or augment oxidative stress and inflammation in DR by comparing these parameters in diabetic and normal age-matched PEDF transgenic mice, PEDF deficient mice and wildtype mice. In Aim 2, we will explore the mechanisms by which PEDF inhibits O2.-/ONOO- formation. We hypothesize that PEDF suppresses diabetes-induced O2.- generation via up-regulation of anti-oxidant enzymes and / or protection of mitochondrial function. If our hypothesis is proved, we will pursue the signaling pathway to explore how PEDF regulates anti-oxidant enzymes and / or how PEDF protects mitochondrial function. If the results indicate that other mechanisms may also contribute to the PEDF effects on anti-oxidation, we will determine alternatively if and how PEDF reduces superoxide generation by inhibiting the major redox enzymes, i.e. NADPH oxidase, xanthine oxidase and eNOS. The success of this project will not only identify a novel pathogenic mechanism for DR, but also contribute to the development of new therapies using endogenous angiogenic inhibitors.